1. Field of the Invention
This invention relates to aqueous solutions of silicon-organic compounds. More particularly, this invention relates to an aqueous solution of a mixture of organosilicon compounds useful as coating agents for metals or inorganic oxidic materials or plastics. More especially this invention relates to agents useful as adhesivizing agents for securing polymeric substances to inorganic oxidic materials. This invention is especially concerned with rendering inorganic oxidic materials, e.g., chalk water-repellent by disposing thereon a composition of organosilicon compounds.
2. Discussion of the Prior Art
It is known that organofunctional silanes are used as adhesivizing agents between inorganic-oxidic material and plastics. For many applications the strength of adhesion thereby obtained suffices. However, if the bond obtained is subjected to special stresses, the adhesion improvement obtained often proves to be insufficient.
Organofunctional silanes have also been used for the protection of the surface of inorganic-oxidic material and metals. Also known is the use of silicon-functional silanes such as, for example, alkyltrialkoxysilanes, in this field of application. It is possible with these silanes to modify the surface of the said materials, which also include inorganic pigments, in such a manner so as to improve free-flowing qualities, for example, by the use of certain silanes. However, the application of these silanes to a number of substrates involved difficulties. For instance, the fixing of these silanes to chalk or other carbonatic or sulfidic pigments is not possible.
Many of the silane coatings hitherto applied to inorganic oxidic material or metals also have the disadvantage that they are sticky, so that they do not provide free-flowing qualities. For the same reason the material has a great tendency to become lumpy. Coatings of aminosilanes are not sticky. These silanes, however, do not have an adequate ability to wet inorganic pigments or inorganic oxidic surfaces, so that they can be applied advantageously only from organic solutions if a uniform coating is to be obtained.
The problem accordingly existed of finding an agent based on silicon-organic compounds which will produce an adhesion between inorganic oxidic surfaces and polymers, and whose effect, even under severe stress-in boiling water, for example, will diminish only slightly.
The problem furthermore existed of finding a substance with which coatings can be applied to inorganic pigments or metal surfaces and which will form on these surfaces a uniform and firmly adherent coating. This coating is furthermore to be hard, and must not be sticky.
It is an object of this invention, therefore, to provide a coating composition for inorganic oxidic materials, i.e., chalk, which improves the surface properties of the chalk and makes the same more compatible with systems in which the chalk is employed. It is a further object of this invention to render such materials at least slightly hydrophobic. It is a further object of this invention to provide an adhesivizing agent for inorganic oxidic materials and polymeric substances which is not substantially adversely affected when the bonded material is subjected to boiling in water over an extended period of time. It is a further object of this invention, therefore, to provide a coating agent for inorganic oxidic substances, inorganic sulfidic substances, metals and polymeric materials. It is especially an object of this invention to provide such a coating substance which is not sticky and adheres well to the coated substrate and has a good wetting ability.
These and other objects of this invention will become more apparent from the following description and claims.